Objective To observe the effect of moxibustion of “Ganshu”(BL18)and “Shenshu”(BL23) on bone mineral density(BMD)

biomechanics

bone metabolism and musculoskeletal morphology of osteoporosis(OP) rats

so as to explore its mechanism underlying treatment of OP via bone-muscle interaction. Methods Thirty-two female SD rats were randomly divided into sham operation

OP model

moxibustion and medication(nilestriol) groups

with 8 rats in each group. For rats of the sham operation group

a small amount of fat around the ovaries was removed

and those of the other 3 groups received removal of bila-teral ovaries for establishing OP model. Moxibustion was applied to bilateral BL18 and BL23 for 30 min

once every other day

3 times a week for 12 weeks. Rats of the medication group received gavage of nilestriol(1 mg/kg) once a week for 12 weeks.After the interventions

a dual-energy absorptiometry was used to determine the BMD and bone mineral content of the rats' right femur and the fourth lumbar vertebrae under anesthesia

and three-point bending test used to detect the biomechanical properties(including load

displacement

stiffness) of the right femur. The levels of serum type I collagen C-terminal peptide(CTX-I)

acid-resis-tant tartrate phosphatase(TRACP) and estradiol(E_2) were determined using enzyme-linked immunosorbent assay

and histopathological changes of the left femur and the quadriceps observed after hematoxylin-eosin(H.E.) staining.Results Compared with the sham operation group

the BMD and bone mineral contents of the right femur and the fourth lumbar vertebra

the load and stiffness of the right femur

and concentration of serum E_2 were significantly decreased(P<0.01

P<0.05)

and the displacement of the right femur

and concentrations of serum CTX-Ⅰ and TRACP notably increased in the model group(P<0.01). After the interventions

the decreased levels of BMD and bone mineral contents

the load and stiffness and concentration of serum E_2

and the increased levels of the displacement

and concentrations of serum CTX-Ⅰ and TRACP were all reversed by both moxibustion(except the bone mineral content of the fourth lumbar vertebra) and medication(P<0.01

P<0.05). No signi-ficant differences were found between moxibustion and medication in up-regulating the levels of BMD and bone mineral contents

the load and stiffness(except serum E_2) and down-regulating the levels of the displacement

and concentrations of serum CTX-Ⅰ and TRACP(P>0.05). H.E. staining revealed that rats in the sham operation group showed mild thinness of the bone cortex

uneven thickness of trabecular bone

with distortion

fracture and osteoporosis of the left femur

and different size of rhabdomyocytes in the right quadriceps femoris muscle

with obvious proliferation of interstitial fibrous tissue and inflammatory cell infiltration

which were relatively and clearly milder in both moxibustion and medication groups.Conclusion Moxibustion of BL18 and BL23 can increase the BMD and bone mineral content

improve biomechanical performance

adjust bone metabolism

and mitigate bone and the attached muscle histopathological changes in OP rats

suggesting that modulating interaction between bones and muscles is probably one of the ideas in the treatment of OP.